Aldo-keto reductase family 1, member B1 (AKR1B1), also known as aldose reductase, is an enzyme that in humans is encoded by the AKR1B1 gene. [5] [6] It is a reduced nicotinamide-adenine dinucleotide phosphate ( NADPH )-dependent enzyme catalyzing the reduction of various aldehydes and ketones to the corresponding alcohol .